How to Install a Fireplace Mantel on a Stone Wall

Sand, prime and paint or stain your mantel pieces and trim, leaving off the final coat of paint or stain.

Assemble the pieces of the mantel kit according to included instructions.

Dry fit the assembled mantel against the fireplace surround, measuring around the fireplace opening to assure that the mantel is squarely centered over the opening.

Draw a pencil line around the edge of the dry-fitted mantel, getting as close to perfectly around the edge of the mantel as possible; draw a line around the inside edges of the mantel, too.

Set the assembled mantel down on a rug or other soft surface, shelf end touching the ground and back side facing you. Measure the width of the mantel shelf and the width of the outermost side ridges of the mantel legs. Note these measurements.

Using a yardstick or other long, flat tool, draw a pencil line inside of the previous mantel outline; the width between the two lines should match the measurements you took for the width of the shelf and the mantel leg edges.

Take measurements of the dimensions of the open spaces between the very innermost lines between the mantel shelf markings and mantel leg markings and subtract 2 inches from each measurement; you will use these measurements to create cleats.

Cut the cleats out of MDF according to the measurements you just took; you should cut out two cleats to which you will attach the mantel legs and one cleat to sit beneath the mantel shelf.

Place the mantel cleat against the wall, directly underneath the innermost shelf line. Using the masonry bit, bore several evenly spaced holes across the length of cleat, running completely through the cleat and creating pilot holes in the stone behind it.

Switch to a Philips head drill bit. Screw 2 1/2-inch concrete screws through your pilot holes, attaching the shelf cleat firmly to the wall.

Set one of the leg cleats against the innermost line on the left side of the fireplace mantel outline. Using your masonry bit, drill pilot holes in even space increments down the length of of the leg cleat, running through the cleat and into the stone beneath. Attach the cleat to the wall using the pilot holes and concrete screws. Repeat on the right side of the fireplace using the remaining cleat.

Fit the assembled fireplace mantel over the cleats; the fit should be snug. Press the mantel against the stone surround firmly to ensure it has a flush fit.

Drive evenly spaced finish screws through the mantel, into the cleat beneath, going completely around all sides and the top of the mantel. Drill the screws deeply enough that they are beneath the surface of the mantel.

Using small nails, attach any remaining decorative trim. Caulk any gaps between the stone fireplace surround and the installed mantel.

Fill the tops of screw and nail holes with wood putty; allow to completely dry. Apply the final layer of paint or stain to complete the process.